1. Field of the Invention
The present invention relates to a liquid droplet discharge head, a manufacturing method thereof, and an image forming apparatus, and more specifically to a liquid droplet discharge head, a manufacturing method thereof, and an image forming apparatus that can prevent an adhesive from blocking a liquid channel by being run off when forming the liquid droplet discharge head by laminating a plurality of plates.
2. Description of the Related Art
An inkjet type image forming apparatus (an inkjet recording apparatus) performs recording by discharging ink in droplet form from a plurality of nozzles (droplet discharge ports) formed in a recording head (a liquid droplet discharge head) onto a recording medium. For such a purpose, ink channels are formed in the interior of the recording head to supply the nozzles with ink from an ink tank in which the ink is stored.
This type of recording head is formed by joining together through lamination a plurality of plate members formed with patterns comprising grooves or holes which form the ink channels and the like. As such a joining method, a method is generally known in which the plate members are joined by coating a joint surface of each plate with an adhesive such as epoxy.
However, according to such the joining method of using an adhesive, the adhesive may run off to the opening side when joining. Therefore, ink discharge cannot be performed appropriately, by narrowing or blocking opening portions such as the ink channels and nozzles.
Conventionally, various methods have been proposed to prevent the adhesive from running off when joining a plurality of plate members to ensure stable ink discharge, such as a method of forming an adhesive escape groove in the plates which form the channels, for example.
For example, Japanese Patent Application Publication No. 5-96726 discloses that an adhesive sump is formed on the outside of the channel hole on the surface of the head substrate having the channel and channel hole that is to be adhered to the plate having the ink discharge hole, when forming an inkjet recording apparatus by adhering a head substrate which has a channel and a channel hole to a plate having an ink discharge hole. Therefore, it is possible to prevent the adhesive from blocking the channel, and then defective adhesion due to fins on the channel plate can be also prevented.
In addition, Japanese Patent Application Publication No. 6-71880 discloses that a non-joined portion (false groove) is provided in at least one of the channel substrate and cover plate to make the joint width around the ink channel substantially constant, when forming a head by joining a cover plate to a channel surface side of a channel substrate which is formed with an ink channel, for example. Therefore, it is possible to reduce the amount of adhesive that runs off or to keep the amount of adhesive that runs off at constant, during the joining process.
Furthermore, for example, Japanese Patent Application Publication No. 7-195693 discloses that an inkjet recording head comprising a barrier formed from a photosensitive resin material, which is used to form a plurality of ink discharge ports and liquid channels on a substrate, and a ceiling plate that is joined to the upper surface of the barrier by an adhesive. The inkjet recording head is provides with grooves capable of accommodating the adhesive that runs off between the upper surface of the barrier and the ceiling plate, and then the grooves are formed at the two edge parts contacting the ink discharge ports and liquid channels on the upper surface of the barrier. Therefore, it is possible to prevent the adhesive from running off around the ink discharge ports.
Moreover, for example, Japanese Patent Application Publication No. 2001-47620 discloses that an inkjet head in which one member comprising an opening portion is joined to another member using an adhesive. In the inkjet head, the joint surface of the first member is formed with a plurality of non-penetrating recesses running along at least an edge portion of the opening portion, and the width of a partition wall between the opening portion and non-penetrating recesses of the first member is set to satisfy a predetermined condition. Therefore, it is possible to prevent the adhesive from running off.
However, in Japanese Patent Application Publication No. 5-96726, when providing adhesive sumps around all of the channels in the adhesion surface of the nozzle plate, it is impossible to form the channels at a high density. Additionally, in Japanese Patent Application Publication No. 6-71880, when the joint width is large, it is necessary for providing a large false groove. Therefore, in addition to consume various times for improving the groove, there is a problem of a decrease in the adhesion strength. Additionally, as described above, when providing false grooves for each channel, it is impossible to form the channels at a high density.
In addition, Japanese Patent Application Publication No. 7-195693 is limited to the photosensitive material. Furthermore, in Japanese Patent Application Publication No. 2001-47620, when providing the non-penetrating recesses around each opening portion for preventing the adhesive from running off, it is impossible to form the channels at a high density.
As described above, when forming adhesive escape grooves and the like around all of the channels for preventing the adhesive from run off, extra labor are required in the formation process. In addition, since the channels cannot be formed each other in close proximity, it is impossible to achieve high density.